1. Field of the Invention
The present invention relates to a guide ring removal device, and more especially to device enabling safer and more convenient guide ring removal.
2. Description of the Related Art
In chemical mechanical process (CMP), a carrier holds and moves a wafer. As shown in FIG. 1, the carrier 100 comprises a cover ring 108, a barrier 106, a holding ring 104, a guide ring 102, a backing film 101, and shims 103, 105, 107.
The cover ring 108, the barrier 106 and the holding ring 104 constitute a pressure chamber. As the carrier 100 holds the wafer, the pressure in the chamber decreases to affix the wafer to the surface of the backing film 101. As a pad polishes the wafer, the pressure chamber imposes back pressure on the wafer to contact the wafer with the pad and improve the wafer polishing effect.
As the pressure chamber imposes the back pressure on the wafer, the guide ring 102 prevents the wafer from slipping. As shown in FIG. 2, as the carrier 100 holding the wafer 150, the guide ring 102 fixes the wafer 150 and keeps it from slipping. In addition, as shown in FIG. 3a, during polishing, the pad 160, under the weight of the carrier, bulges upward around the periphery of the wafer. Without the guide ring 102, this bulging promotes over-polishing on an edge portion 155 of the wafer 150. As shown in FIG. 3b, the guide ring 102 is provided, spreading the polishing surface, to prevent the edge portion 155 of the wafer 150 from excess contact with the pad, thereby avoiding over-polishing of the wafer.
In carrier maintenance, the guide ring 102 must be separated from the carrier 100. However, the slurry and the chemicals used in polishing and particles generated thereby can adhere the guide ring 102 to the carrier 100, making separation of the guide ring 102 difficult. Conventionally, the guide ring 102 is separated by prying, requiring undue time and effort, possible damage to the guide ring 102 and the carrier 100, and presenting possible safety risks.
For these reasons, there is a clear need for a device enabling safer and more convenient guide ring removal.
The present invention includes a column press, a first disc, a second disc, and a plurality of fasteners. The first disc is disposed on the column press. The second disc is disposed on a point of the column press to exert force on a carrier. The plurality of fasteners is disposed on the first disc, grasping the guide ring. As the second disc exerts the primary force on the carrier, the fasteners generate reciprocal force on the guide ring, thus separating the guide ring. Engagement of the column press alters the distance between the first disc and the second disc, and the primary force is exerted on the carrier.
With the present invention, guide ring separation is rendered easier and safer, and damage to the guide ring is avoided.